| 摘要 |
PROBLEM TO BE SOLVED: To prevent distortion of a driving waveform caused by signal reflection of a driving electric current. SOLUTION: In the driving circuit, a plurality of light emitting thyristors 210 (=210-1 to 210-n) constituting a light emitting element array 200 are connected in parallel between a VDD terminal and a common terminal IN. The common terminal IN is connected with a constant current source circuit 42 through a connection cable 70. In addition, between an anode and a cathode of the light emitting thyristor 210, a switch circuit 230 is connected. The light emitting thyristors 210-1 to 210-n are successively turned on by trigger signals successively output from a shift register 110. In this instance, based on an on/off command signal DRVON-P, the switch circuit 230 is turned on to short-circuit between the anode and cathode of the light emitting thyristor 210, when the light emitting thyristor 210 is turned off, and the switch circuit is turned off when the thyristor 210 is turned on. Thereby, the driving electric current Iout flowing into the connection cable 70 becomes approximately constant, and no signal reflection exists. COPYRIGHT: (C)2011,JPO&INPIT |
